Machine for grinding the rim of a spectacle lens

ABSTRACT

A machine for grinding the periphery of a spectacle lens, and the like, in which rough and fine grinding discs are mounted on a sleeve which is non-rotatably but axially moveably connected to a drive shaft. Abutment means on the sleeve and shaft determine one axial position of the sleeve relative to the shaft in which the rough grinding disc is effective while the sleeve is permitted to float axially of the shaft while the fine grinding disc is effective thereby to permit the disc to follow the contour of the periphery of the lens being ground.

. United States Patent [191' Meckler et a1. 1

[111 3,775,908 Dec. 4, 19-73 MACHINE FOR GRINDING THE RIM OF A SPECTACLE LENS I [75] Inventors: Helmut Meckler, Dusseldorf; Hans Gunter Barwasser, Norf, both of Germany [73] Assignee: Wernicke & Co. KG, Dusseldorf,

Germany 22 Filed:. Jan.25,1972

21 Appl.No.:220, 618

[52] US. Cl. 51/72 R, 51/101 LG, 51/168 [51] Int. B24b 9/14 [58] Field of Search 51/172 R, 72 L, 101 R,

51/101 LG, 105 R, 105 EC, 105 LG, 106 R, 106 LG, 34 R, 34 H, 34 A, 50, 51,168, 102

[56] References Cited UNITED STATES PATENTS 3 1927 Maynard 51 101 LG 1,672,573 6/1928 Maynard 51/101 LG 2,747,337 5/1956 Geula 51/101 LG 3,332,172 7/1967 Stern 51/101 LG Primary Examiner-Harold D. Whitehead Assistant ExaminerNicholas P. Godici Attorney-Walter Becker 5 7 ABSTRACT A machine for grinding the periphery of a spectacle lens, and the like, in which rough and fine grinding discs are mounted on a sleeve which is non-rotatably but axially moveably connected'to a drive shaft. Abutment means on the sleeve and shaft determine one axial position of the sleeve relative to the shaft in which the rough grinding disc is effective while the sleeve is permitted to float axially of the shaft while the fine grinding disc is effective thereby to permit the disc to follow the contour of the periphery of the lens being ground.

9 Claims, 1 Drawing Figure PATENTED 75 I s I MACHINE FOR GRINDING THE RIM or A SPECTACLE LENS The present invention relates to a machine for grinding the rim or edge of a spectacle lens, which comprises a rough grinding disc which is non-rotatably mounted on a driven shaft to turn therewith but is axially nonmovable, and which furthermore comprises an axially movable fine grinding disc which generally is a bevel grinding disc. With non-circular lenses, this fine grinding disc carries out an axial movement inasmuch as the bevel follows a three-dimensional curve.

Machines for grinding the rim of a spectacle lens are known according to which on a driven shaft there are arranged the axially non-movable rough grinding disc and the adjacent likewise axially non-movable fine grinding disc. A fine grinding disc will continuously engage the rim of the spectacle lens having the sections thereof located on. a three-dimensional curve. The fine grinding disc will continuously engage the rim of the spectacle lens due to the fact that the lens is freely movable in its axial direction. To this end, the spectacle lens is mounted in a lens holder which is adjustable parallel to the shaft of. the grinding disc or is mounted in a pivotable lens holder. The lens holder is on one hand arrestable for the rough grinding operation, whereas for the fine or bevel grinding operation the lens holder is freely displaceable in the longitudinal direction of the shaft or is freely pivotable in this direction. When reversing this arrangement of the grinding discs and the spectacle lens, it would be possible to axially displace the shaft driving the grinding discs and to arrest and hold the lens axially non-movable. During the rough grinding, the shaft with the two grinding discs would be kept axially arrested, whereas during the fine or bevel grinding the shaft with the two grinding discs would be freely longitudinally movable.

The heretofore known machines with pivotable lens holder and with a lens holder displaceable parallel to the shaft for the grinding discsas well as the above mentioned possible design with an axially movable shaft for the grinding discs have the drawback that when the parts are freely adjustable, a relatively great mass has to be placed into motion so that the counter or adjusting forces exerted upon the bevelrims or the It is, therefore, an object of the present invention to provide a machine for grinding the rim of a spectacle lens of the above mentioned general character according to which the adjusting forces occurring when fine grinding can be kept low without a positive guiding of the rim of the spectacle lens, especially when bevel grinding, so that the parts of the machine which have to move axially will be able to precisely follow the path of the three-dimensional curve of the rim of the spectacle lens. In other words,,it is an object of the present invention to provide a machine for grinding a spectacle lens of the above mentioned general type in such a way that the forces acting upon the rim of the lens and necessary for adjusting the corresponding machine parts will be reduced to a minimum so that in addition to the quality and precision of the finely ground section it will also be possible to accelerate the fine grinding process. It is a further object'of this invention to provide a grinding machine as set forth above which will be of a simple and relatively inexpensive structure.

These and other objects and advantages of the inven tion willappear more clearly from the following specification in connection with the accompanying drawing which illustrates an embodiment of the machine according to the invention in which the two guiding discs are together arranged on a bushing which is displaceable on, the drive shaft for the grinding discs.

The machine according to theinvention is characterized primarily in that the finegrinding disc is freely displaceable or adjustable on the driven shaft and by means of an axial drive is held against an abutment in longitudinal direction of the shaft or is held on the shaft.

In view of the free displaceability of the fine grinding disc on the shaft it will be assured that during the fine grinding operation only those forces act upon the rim of the spectacle lens which are necessary exclusively for adjusting the fine grinding disc and the parts of the axial drive of the disc.

Inasmuch as for placing the rim of the spectacle lens against the fine grinding disc, the latter must occupy an axially non-displaceable position, it is necessary to move the fine grinding disc first against an axially nonmovable abutment so that thereupon the spectacle lens canbe precisely inserted'into the bevel of the bevel grinding disc. This is the case particularly when the transfer from the rough grinding disc to the tine grinding disc is effected automatically and in connection therewith it must be assured that the spectacle lens is lowered into the bevel groove.

According to a further development of the invention, the fine grinding disc is mounted on antifriction bearings on the shaft. These bearings form an axial guiding means so that the resistance against the displacement of the fine grindingdisc will be kept low.

The same purpose is intended to be realized by a further feature of theinvention which is characterized in that the fine grinding disc is journalled by means of a roller pair of a follower. The roller pair is guided in guiding paths, non-rotatably but axially slightly displaceably connected to the shaft. I

Preferably, the fine grinding disc is adjustable on the shaft by means of an electromagnet. In this'connection,

the connecting rod extending into the magnet is journalled on or in the magnet by means of'antifriction bearings so that all parts whichare axially displaceable on the drive shaft for the grinding disc are easily'longitudinally adjustable.

According to a particularly advantageous design of the machine according to the present invention, the fine grinding disc and the rough grinding disc are arranged together on-a bushing which is axially displaceable on the drive shaft for the grindingdiscs, the bushing being'n'on-rotatably. connected to the shaft so as to be rotatable therewith.

Preferably the follower is formed by a transverse bolt of the shaft and at its free-ends which protrude from the shaft carries rollers which are adapted to roll on the guiding path for the bushing.

Referring now to the drawing in detail, the shaft housing 1 in the direction of the double arrow A is adjustable by the stroke X, Y together with a nonillustrated drive motor for the shaft 3. Shaft3 has one end journalled in housing 1 by means of a bearing 4 against which directly or indirectly rests a spring 5. Spring 5 is arranged in the cylindrical hollow chamber 6 of housing 1 and has its second counter bearing formed by a sleeve 7 which similar to the spring 5 surrounds the rear portion of shaft 3, the sleeve 7 resting against an adjustable set screw 7a. In front of sleeve 7, shaft 3 has an annular bead 8 in front of which there is arranged in housing 1 an inner ring of a double-groove roller bearing 9, whereas the outer ring of the bearing 9 rests against an annular portion 10 which issecured in housing 1 against axial movement.

From the front end of housing 1 there protrudes a driving disc 11 which is non-rotatably connected to shaft 3 so as to rotate therewith. Disc 11.has an annular groove 12 for a rope drive, belt drive, or the like.

Approximately the central section of shaft 3 is provided with a thread 13 on which is screwed a threaded nut 14 the left-hand end face of which (with regard to the drawing) rests against the driving disc 11. Between nut 14 and a further nut 15 screwed onto the thread 13 of shaft 3, there is provided the inner end of an undulated folded seal 16. At the end of the thread 13'there is provided a threaded ring 17. Instead of the nuts 14, 15, also threadless rings may be employed which by the threaded ring 17 are pressed against. the driving disc 11.

Mounted on the front section 3a of shaft 3 there is an anti-friction bearing 18 which makes it possible for a bushing 19 to be easily displaced on shaft 3 in the direction of the double arrow B. The bushing 19 has its front end provided'with two wide slots the walls 20 of which (the drawing showing only one wall of each slot) form a guiding path for the rollers 21 which are journalled on the free ends of a pin 22 which extends through the front end of shaft 3. Therefore, when shaft 3 is turned, the bushing 19 is non-rotatably carried along by the shaft. In view of the bearing 18 and the rollers 21, a slight displacement and guiding of bushing 19 will be possible. Bushing 19 is secured by a sleeve 23 and is connected with the latter. The rear end of sleeve 23 has mounted thereon a mantle member 24 which at the level of the thread 13 surrounds shaft 3. The outer marginal portion of the folded seal 16 is held between flange 25 of mantle member 24 and sleeve 23.

The wall 26 of the end face of sleeve 23 is engaged. by a connecting rod 27 of an electromagnet 28 which is connected to the housing 1. Preferably, the rod 27 is journalled in or on the magnet by antifriction bearing means so that the parts which are longitudinally movable on the shaft will not cause any great displacement resistance. The rough or coarse grinding disc 29 and the two bevel grinding discs 30, 31 are arranged on sleeve 23. However, any other suitable arrangement of the rough or coarse grinding discand the fine grinding discs may be selected.

Mounted on sleeve 23 is a housing 32 which will assure a safe seal of bushing 23 and sleeve 19.

The operation of the machine according to the present invention is as follows: housing 1 with shaft 3 and bushing 19 and sleeve 23 are moved into a position in which for rough or coarse grinding the spectacle lens. The rough or coarse grinding disc 29 is located at the level of the rotatable but axially non-displaceable lens. The magnet 28 will be energized so that the bushing 19 and the sleeve 23 are displaced toward the left (with regard to the drawing) and the end face edge 33 of sleeve 19 will engage ring 17. As a result thereof the grinding discs 29, 30, 31 are fixed as to their longitudinal position relative to shaft 3 and housing 1 so that the pre-grinding operation can be carried out by means of disc 29.

After completion of pre-grinding or rough grinding, the spectacle lens is removed from'the rough grinding disc 29; then the housing 1 with shaft 3, bushing 19 and sleeve 23 is moved toward the right (with regard to the drawing) by the distance Y or X together with the drive motor adjustment mentioned earlier so that the spectacle lens will now be located at the level of the disc 30 or 31. When the lense is lowered into the predetermined bevel groove 34 or 35, the magnet 28 will be deenergize d so that the connecting rod 27 will in view of a spring provided in magnet 28 move toward the right approximately by 12mm. In the meantime, housing 1 and shaft 3 are moved back in accordance with the foregoing manner of adjustment (toward the left with regard to the drawing) by approximately 6 mm. A carrying away of the discs 29, 30, 31 will be impossible because the spectacle lens has already been inserted into the bevel groove.

When finish grinding the lens, the discs 29, 30, 31 can easily be'moved axially and can follow the threedimensional curve which is determined by the circumferential contour of the respective lens without encoun tering any material frictional resistance. It is, of course, to be understood that the present invention is, by no means, limited to the particular showing in the drawing but also comprises any modifications within the scope of the appended claims.

What is claimed is: v

1. In a machine for grinding the periphery of a spectacle lens and the like in which the said periphery is undulating when the lens is viewed from the side; a housing, a shaft rotatable in the housing, a sleeve coaxial with said shaft and nonrotatably connected thereto but axially moveable relative thereto, rough and fine grinding disc means on said sleeve, cooperating elements of abutment means on said sleeve and said shaft predetermining one axial position of the sleeve relative to the shaft, and means connected to said sleeve and operable for holding said cooperating elements of abutment means in engagement during rough grinding by said rough grinding disc means and for releasing said sleeve for axial movement relative to said shaft during finish grinding by said fine grinding disc means.

2. A machine according to claim 1 in which said sleeve surrounds said shaft, and antifriction bearing means interposed between said sleeve and said shaft and axially guiding said sleeve on said shaft.

3. A machine according to claim 1 in which said sleeve comprises axial slot means therein, and drive roller means on said shaft engaging said slot means and esjournaled for free rotation in at least one of said sleeve and electromagnet.

6. A machine according to claim 1 in which said rough and fine grinding disc means are fixedly clamped to said sleeve.

7. A machine according to claim 1 in which said sleeve comprises axial slot means therein, and drive roller means on said shaft engaging said slot means and establishing driving connection of said shaft to said sleeve, a bolt extending transversely through said shaft, said roller means including a roller rotatable on each end of said bolt, said slot means comprising slots in said sleeve in diametrally opposed relation and each receivmeans. 

1. In a machine for grinding the periphery of a spectacle lens and the like in which the said periphery is undulating when the lens is viewed from the side; a housing, a shaft rotatable in the housing, a sleeve coaxial with said shaft and nonrotatably connected thereto but axially moveable relative thereto, rough and fine grinding disc means on said sleeve, cooperating elements of abutment means on said sleeve and said shaft predetermining one axial position of the sleeve relative to the shaft, and means connected to said sleeve and operable for holding said cooperating elements of abutment means in engagement during rough grinding by said rough grinding disc means and for releasing said sleeve for axial movement relative to said shaft during finish grinding by said fine grinding disc means.
 2. A machine according to claim 1 in which said sleeve surrounds said shaft, and antifriction bearing means interposed between said sleeve and said shaft and axially guiding said sleeve on said shaft.
 3. A machine according to claim 1 in which said sleeve comprises axial slot means therein, and drive roller means on said shaft engaging said slot means and establishing driving connection of said shaft to said sleeve.
 4. A machine according to claim 1 in which said means connected to said sleeve comprises electromagnet means connected to said sleeve for effecting axial movement thereof.
 5. A machine according to claim 1 in which said means connected to said sleeve comprises electromagnet means connected to said sleeve for effecting axial movement thereof, said electromagnet including a rod coaxial with said sleeve and connected thereto and journaled for free rotation in at least one of said sleeve and electromagnet.
 6. A machine according to claim 1 in which said rough and fine grinding disc means are fixedly clamped to said sleeve.
 7. A machine according to claim 1 in which said sleeve comprises axial slot means therein, and drive roller means on said shaft engaging said slot means and establishing driving connection of said shaft to said sleeve, a bolt extending transversely through said shaft, said roller means including a roller rotatable on each end of said bolt, said slot means comprising slots in said sleeve in diametrally opposed relation and each receiving a respective roller.
 8. A machine according to claim 1 in which said housing is bodily moveable in the axial direction of said shaft.
 9. A machine according to claim 1 in which said sleeve surrounds said shaft, and antifriction bearing means interposed between said sleeve and said shaft and axially guiding said sleeve on said shaft, and axially flexible seal means connected between said shaft and said sleeve and sealing the space therebetween to exclude foreign matter from said antifriction bearing means. 